Fix lunch choices for git_main

We add "trunk_staging-" for all COMMON_LUNCH_CHOICES so they are
valid in the trunk stable setup.

Bug: 307738446
Test: lunch
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a3a8befa9531ee35d5c2a57b65b4f73e08d8e7bb)
Merged-In: I81187827ee2a98a9efa19a0f729f1c7d17c01aaa
Change-Id: I81187827ee2a98a9efa19a0f729f1c7d17c01aaa
7 files changed